Isn't op... if you really know the champ as i do... you know all his power comes from his q with 5 of fury,,, after use it... it's just a mental thing... (should i scape or fight? the f*ck).
Also, you should know already he's a predator in the jungle... ooooooohhhhh rengar just went into bushes with 100 life i can kill him ... (but he has 5 of fury... so he's going to kill you)... champs that counter him badly... amumu (all the game), jarvan after 10 (no feed rengar), cho after 6, tryndamere after 6... in late game ryze, le blanc, anivia, garen, rammus and skarmer.
If you think rengar is op, you should be a 100% percent carry player... rengar has only 1 mision take the carry out of the fight... and if he survive, kill the tank. cya ^^